Process of corrugating cylindrical bodies



ments in Processes iol cylindrical wall 415-l gardless of thiscondition, it is preferred arreste wiLLuu n cnALFANr,

0F GLENSIDE, PENNSYLVANIA, ASSIGNIB. T0 LANSTN MONOTYPE MACHINE COMPANY,0F PHILADELPHIA, PENNSYLVANIA, A

PORATION l0F VIRGINIA.

PROGESS '0F COBBUGATING GYLINDRICAL BODIES.

To all whom t may concern Be it known that I, WILLIAM E. CHAL- FAN'r, acitizen of theUnited States, residing at Glenside, in the county ofMontgomery and State of Pennsylvania, have .invented certain new ofCorrugating Cylindrical Bodies; and I do hereby declare the following tobe a clear, and exact description of the saine, reference being had tothe accompan. gA drawings, forming part of this speci cation.

This 'invention relates to the art of corrugating metal by bending, andvmore especially to that branch of the art having to do with thecorrugation of cylinders. rEhe practical development of the inventionhas been along the lines of corrugating water jackets for machine guns,and while it will be described in connection with the production of thisclass of devices it will be understood that the invention may beemployed in the corrugating of vany cylindrical or other bodies whichare endless in cross section or which'have a curvature, the'general formof which it is desired to preserve.

In carrying the invention into practice thecylindrical wall isinternally supported at points opposite the external crests of de.sired'external corrugations and then exter-j nal pressure is applied tosaid wall between the points of support throughout the area to becorrugated with the resultl that the cylindrical wall is deflectedinwardly lto form external valleys. of the process especially where itis desired to secure great regularity and uniform' of the corrugations,without setting up objectionable strain in the metal, the inward bendinof the wall between the supports is at or not carried beyond a pointwhere the neutral axis of the bent metal wall equals inlen h the neutralaxis of the efore 'bending and, re-

that the .bending shall be performed in successive stages, thecylindrical wall being first supported on the inside at points which arespaced apart a greater distance than the distance between adjacentcorrugations and after the wall has been pressed inwardly in theintervals, the points of internal support are shifted to the inwardlydeflected portions of the wall and external pressure apand usefulImprove-v In the refinements` Specicatiouot Letters Patent: Patented May17, 1921- Application led November 16, 1917. iserial. No. 202,327. I

plied to force'the previously supported por- 55 tions of the wallinwardly. The ultimate internal support should, especially whereaccuracy and uniform appearance is desired, conform to the internal faceof the wall in its final corrugated form, and the logical and mosteiicient means for applying uniform external pressure is a hydraulicpress in which the liquid' bears directly against the external face ofthe wall.

In the accompanying drawings,-

Figure 1 is a transverse section of a cylinder having within it asupport in the form of'a sectional mandrel, the contour of whichcorresponds to the shape of the cylinder,C after external. pressure hasbeen applied. 'L

Fig. 2 is a similar -view after external pressure has been applied,

Fig. 3 is a similar view with a support in the form of a sectionalmandrel, the contour i of which corresponds to the inal shape to begiven the cylindrical body andvwith which the mandrel engages at theinwardly deiected parts.

Fig. 4 isa similar. view after external pressure has been applied.'

Figs. 5 and 6 are a transverse and a longitudinal section of a hydraulicpress cylinder with a corugated machine gun water )acket in p ositiontherein.

Fig. 7 is a detail section near one end of a water jacket cylinderbefore being corru- Y Fig. 8 is a similar view after corrugation. Likereference characters indicate the same parts in the several iigures. 490 In the drawings adopted for illustrating the invention, the internalsupport for the cylindrical wall is in the form of a sectional mandrelpreferabl made up of ive sections,

four of which, in icated by the numerals 1, v t

`2, 3, and 4, in Figs. 1 and 2, and by 1, 2, 3,

inner side of the cylindrical wall at points where alternate externalridges will be formed, and these points on the mandrel may be termed thehigh ribs or ridges 6. Between the high ribs 6 valleys are formedinwhich are ribs or ridges 7 of lessheight than the ribs .6, andpreferably of a height which will correspond to the height of the ribsor ridges which -will determine the height of the corresponding externalridges or corrugations of the final product. Having placed the mandrelin position, the jacket vand mandrel are now placed in the cylinder -.C.of the hydraulic pressand uniform external pressure applied,vwith theresult that the cylindrical wall is forced inwardlyV against the mandrelas shown in Fig. 2. The mandrel is then removed and the mandrel shown inFigs. 3 to 5 inserted. This mandrel has its contour formed to give thefinal shape to the cylindrical wall and it will be noted from F ig. 3that the ribs or ridges of the mandrel initially-support the wall atthose points where it is deflected inwardly and register with or litinto the low ridges of the said wall. Thejacket and .mandrel -are nowinserted in the press cylinder C and external pressure again applied,thereby deflect.- ing the previously supported portions of the wallinwardly and completing the formation of the corrugations.

In the preferred contour lines and pro-v portions the neutral axis ofthe cylindrical wall and of the corrugated wall are of the same lengthand this is also true with respect to the intermediate stage shown in Fig. 2. As a result the metal as a whole forming the cylindrical wall isnot stretched or condensed, but its original 'uniform thickness andstrength is preserved inthe'finished product.

Where, as in the formation of va water jacket for machine guns, thecorrugations terminate short of the end of the cylinder, as in theexample shown in the drawings, it is preferable to preliminarily shape,by cutting, those portions of the wall 'at the ends of the corrugationsin such wise that the wall will be simply bent into the desired sha-peand the length of the neutral axis will be substantially the same in theblank and in the finished product.

The formation which in practice hasbeen found to accomplish the desiredend is shown in Fig. 7. and the'change in the for` mation by corrugatingis shown in Fig. 8. c; In said figures it will be seen that the wallincreases in thickness and .decreases in diameter at B in. Fig.. 7, andwhen corrugated the reduction in diameter of the cylinder at theexternal crests of the ridges y provides the necessary metal for thevalleys,

' leaving the neutral axis of the wall of .sub-

stantially the same length and the gradual v tapering away of thecorrugations is in pronatascia portion to the diameter of the cylinderand consequently the corrugations may be formed with the imposition ofminimuml strains in the metal of the'wall. In fact, it is thoughtsubstantially the only strains are those due to the bending of the metalwall and exist only on opposite sides of the neutral axis.

By providing metal supports for the cylindrical wall, both when incylindrical form as in Fig. 1, and when at the intermediatestage, as inFig. 3, the uniformity of the action of the external pressure is insuredand by spacing the points of support a very considerable distance apartthe area of the wall exposed for deflection is vastly increased and thepressure required is correspondingly less to accomplish the desireddeformation. v

What is claimed is:

1. The process of forming corrugated cylinders in which the corrugationsform arcs of less radius than the radius of the cylinder, which consistsin supporting the internal face of the cylinder wall along linesopposite the crests of desired corrugations, simultaneously applyingpressure to the external face of said wall between the lines of supportand thereby bending said wall inwardly between the points of support,supporting the internal face of the inwardly bent portions of the walland thereby preventing elongation of the neutral axis dueto the bendingmovement and then removing the external pressure and interna-1supporting means. `2. The process of corrugating a cylindri- Ical bodywhich consists in supporting said body on the interior at pointsspacedfrom each other a distance greater than the distance betweendesired adjacent corrugations, then applying vexternal pressure andforcmg the cylindrical wall inwardly between the lpoints of support,then supporting the inwardly deflected portions of said wall, and

-finally applying external pressure and forcing the previously supportedportions of the wall inwardly. i

3. The' process of corrugating a cylindrical body whichconsists insupporting. said 'portions of the wall inwardly.

4. The process of forming corrugated cylinders with corrugations havingVarcs of 130 r body on the interior at points spaced from curvature ofless radius than the radius of the cylinder which consists in. applyingpressureto the external face of the cylinder wall, supporting theinternal face 'of said wall at intervals spacedI from each other topermit 'the said wall to bend inwardly between the points of supportwithout stretching the material forming the cylinder and increasing thelength of the neutral axis and in arresting such bending of the'wallwhen the neutral axis is of Sub-v stantially the length of the neutralaxls of the wall of the cylinder before bending.

tions,

cal body, which. consists iny supporting said body onthe interior atpoints opposite alternate external'crests of desired corruga- Y thenapplying external pressure and forcing the cylinder wall inwardlybetween the points of support, then supporting the inwardly deflectedportions of the wall at points opposite the external crests of desiredcorrugations and finally applying external pressure and forcing thefirst supported portions ofthe wall inwardl WILLIAM E. CHALF y NT.

